plow under vs pommel

plow under

verb
  • To destory (crops) by turning them into the ground with a plow 

pommel

verb
  • To pound or beat. 

noun
  • Either of the rounded handles on a pommel horse. 

  • The knob on the hilt of an edged weapon such as a sword or dagger. 

  • The upper front brow of a saddle. 

  • A knob forming the finial of a turret or pavilion. 

How often have the words plow under and pommel occurred in a corpus of books? (source: Google Ngram Viewer )